Munster shocked over handling of Yeo knock

The fallout from Yeo's series-opening tackle continued on Thursday, with NSW advisor Greg Alexander admitting he also thought the Blues star should have been taken off and the incident had affected the player.

In a brutal first hit, Yeo's head appeared to make contact with Josh Papalii before he fell backwards and lost his balance in retreating to the line.

He was also assisted by Blues teammate Tariq Sims as he regathered stable footing, before resuming his place in defence.

Yeo was allowed to stay on the field, with the NRL's independent doctor only wanting a category-three on-field check rather than requiring a 15-minute off-field check with a category two or ruling him out of the match with a category one.

Yeo insisted afterwards he was not concussed and said he had merely lost his balance on the slippery surface as he got up.

Munster claimed the incident was similar to the one that forced him to be ruled out of Game II in 2020 after two minutes, and was a bad look for the game.

"It wasn't rocket science, you could see he wasn't well," Munster said.

"It makes me sick (to see it) but someone's got to put their hand up and take responsibility for it, cause it's not on.

"We've been speaking about it for years and years about the welfare of our players and our heads.

"You want to showcase that in the biggest game of the year."

Under NRL protocols possible head knocks are spotted before an independent doctor in the bunker pores over replays from different angles.

Motor incoordination such as balance disturbance and clumsiness are considered as indicators that require a player to be checked.

"I know it's an Origin game ... but someone's got to take a stand," Munster said.

"I didn't want to go off (in 2020), I passed all my HIAs and everything, but because I stumbled and wasn't right they pulled me."

NRL's head of football Graham Annesley said the incident had been assessed with the game's chief medical officer and indicated the league was okay with the process.

"While there were indicators that could have supported a category-two assessment, the decision to have the team medical trainer conduct an on-field check did not reveal any signs that an off-field HIA was required," Annesley said.

"This decision was supported after a further check by NSW medical officer, Nathan Gibbs, at halftime and again at fulltime, with the player not exhibiting any symptoms of concussion."

While medical officials in the bunker had access to replays showing Yeo stumbling to the line, it has also emerged they were not shown to NSW officials on the sideline.

Yeo has a history with concussions, but was insistent after the Blues' 16-10 loss he was not suffering side-effects of a head knock following the tackle.

"I felt fine," he said.

"I remember everything, I've been knocked out and it definitely wasn't that. I just lost a bit of balance.

"(It was) just the contact, I reeled out of it and I was just trying to get my footing to get back in the line."

Australian Associated Press